Add new autotest for UI respawning behavior

Since we moved UI respawning management into a separate job,
instead of using the default upstart behavior, we need a test
to validate that it works.

CQ-DEPEND=I5c15f2e99e26defb1458ca2d6b23721fd181ef06
BUG=chromium:261784
TEST=run desktopui_Respawn

Change-Id: Iba61ecf10319f07ef6ed7a1d5204ecdb368fcbef
Previous-Reviewed-on: https://gerrit.chromium.org/gerrit/64663
(cherry picked from commit 545acb42da0c358dea4a3279408cca1f67d1cd4e)
Reviewed-on: https://gerrit.chromium.org/gerrit/65209
Commit-Queue: Chris Masone <cmasone@chromium.org>
Reviewed-by: Chris Masone <cmasone@chromium.org>
Tested-by: Chris Masone <cmasone@chromium.org>
3 files changed